1.Could someone please explain, in layman's terms, what are the differences between getTransportTime / getBackwardTransportTime, and getTransportCost / getBackwardTransportCost?

Initially, I've wrongfully thought that this is used in case of an asymmetrical time / distance matrix, e.g. I thought that getTransportTime is used to check time from A to B and getBackwardTransportTime is used to check time from B to A.